The present invention is directed to a radiological apparatus for imaging of an object, and in particular, to a mammography apparatus with detection of compression pad, i.e., a mammography apparatus in which an operator positions the compression pad on its support, and the mammography apparatus will automatically set the parameters for the pad.
A radiological imaging apparatus, such as a mammography apparatus, is an apparatus used to take images of a patient's breast by means of radiation. In practice the apparatus comprises a vertical column bearing a breast-support tray on which the patient breast is placed so that an image can be taken. Beneath the breast-support tray, there is a means for detection, usually a cartridge with a photosensitive film or a digital means, as well as various devices to limit undesirable effects in the image. The top of the column bears means for providing a source of radiation, such as an X-ray tube, whose ray of radiation are directed toward the means for detection.
The acquisition of the mammography image, designed in particular to reveal the presence of microcalcification, which may be evidence of incipient cancer, might be efficient only under certain conditions. One of the conditions is the hardness of the X-rays. The X-rays must be of a hard type so that the image obtained reveals the structures to be detected with sufficient contrast. Furthermore, for reasons of both stability and image quality, the patient's breast has to be compressed. Various compressive forces may be applied. These forces are applied through a compression pad that compresses the breast on the breast-support tray, according to the type of image/examination to be made.
A given type of pad is therefore related to a type of image/examination. Furthermore, a pad is also described at least by its intrinsic properties, namely its shape, dimensions and the absorption characteristics of the material in which it is made. These characteristics of the pad are important because the stream of X-rays travels through the pad before reaching the breast and then the X-ray sensitive receiver/detector making the measurement/image. It is therefore important to be able to take account of these characteristics for the exploitation, or production, of the images resulting from the examination.
In the prior art, the physical characteristics of the compression pad are taken into account either by the operator examining the images or by an algorithm for processing the acquired data and the physician. Whatever the specific situation, the physician must be given reading keys and the algorithm must be provided with processing parameters. These reading keys, or parameters, pertain to the nature of the examination, i.e., they depend on the nature of the view. The views are classified as a function of ranges of angle and position of the image receiver with respect to the breast. Each of these views has a name enabling it to be identified rapidly and simply. For example, there are MLO views (medio-lateral-oblique views of the breast). There also exist Spot views: these are magnified views made with small pads because the observed zone is small. The pads are then called Spot pads. The list of views/examinations is not exhaustive.
In the prior art, the operator at a panel connected to the mammography apparatus enters the parameters, or they are viewed on the image through the interposition, between the detector and the radiation source, of an opaque plate comprising a message used to identify the parameters of the image. Manipulations of this kind entail painful waiting periods for the patient while the breast is compressed. Furthermore, the operator is liable to commit information-recording errors that give rise to confusion during the analysis of the images. Indeed, a key assumes all its significance as a function of these interpretation keys. If these keys are poor, it becomes impossible to interpret the picture and therefore to carry out a diagnosis. At worst, this may lead to a wrong diagnosis. The fact that an operator often has to carry out operations to set the parameter of the apparatus increases the possibility of error through the establishment of routine or of lassitude.